UML modeling support provided by IntelliJ IDEA involves two aspects:
UML model in IntelliJ IDEA is represented by a Class diagram in standard notation.
IntelliJ IDEA enables using UML class diagrams to analyze Java, JavaScript, ActionScript/Flex, PHP, and Maven applications, and the structure of the databases and tables. Besides that, you can explore changes committed to VCS.
In IntelliJ IDEA, Class diagram features:
In the editor, one can view class diagram for the whole class, or for a symbol at caret.